@article{fdi:010075529,
title = {{M}agma propagation at {P}iton de la {F}ournaise from joint inversion of {I}n{SAR} and {GNSS}},
author = {{S}mittarello, {D}. and {C}ayol, {V}. and {P}inel, {V}irginie and {P}eltier, {A}. and {F}roger, {J}. {L}. and {F}errazzini, {V}.},
language = {{ENG}},
abstract = {{M}agma propagation is an unsteady process controlled by magma-crust interaction. {T}o provide information on its dynamics, we invert complementary ground deformation data spanning the 8hr preceding the 26 {M}ay 2016 eruption at {P}iton de la {F}ournaise ({P}d{F}) volcano ({L}a {R}eunion, {F}rance). {D}ata are inverted using 3-{D} boundary element models combined with a {M}onte {C}arlo inversion method. {T}he final geometry of the displacement source is determined based on four interferograms spanning the whole propagation phase while the dynamics of the propagation is inferred from temporal inversion of continuous {G}lobal {N}avigation {S}atellite {S}ystem ({GNSS}) data, using the final geometry as an a priori to constrain the source. {T}he best modeled magma path consists in a 2,700-m-long sill located 800m above sea level and connected to the eruptive fissure by a subvertical dike. {T}he quick opening of the horizontal part of the intrusion could have been favored by limited flank sliding during the early stage of propagation. {T}he intrusion then stalled for approximate to 5hr, while pressure increased slightly, until final upward propagation and eruption. {V}olume budget suggests that the eruption was fed by a single batch of magma quickly disconnected from its source. {T}he delay prior to the eruption may reflect a limited magma supply. {F}inally, two mechanisms, potentially acting together, might have favored the eruption: a driving role of magmatic gas and/or, as often observed at {P}iton de la {F}ournaise, an eastward flank slip. {P}lain {L}anguage {S}ummary {B}asaltic magma stored beneath volcanoes reaches the surface by fracturing the {E}arth's crust. {A}s experienced in {M}ay 2018 at {K}ilauea volcano ({H}awaii, {USA}), magma can travel kilometers from the reservoir and fissure opening may threaten man-made structures. {A}nticipating where and when eruptive fissures open requires better understanding of the factors controlling magma propagation. {D}uring the 26 {M}ay 2016 eruption of {P}iton de la {F}ournaise, {R}eunion {I}sland,the preeruptive crisis spanned 8hr25min from the first signal recorded by the observatory to the eruption onset.{W}e determine the magma paths and propagation timing, which led to this eruption using complementary satellite data of ground surface displacement, combining radar interferometry, which provides high spatial resolution, with {GPS}, which provides high temporal resolution. {W}e highlight complex magma propagation within the subareal volcano, showing two direction changes, an arrest and an acceleration. {F}lank slip and magma degassing seem to play a key role in controlling both the geometry and the timing. {B}ased on this scenario, this event was close to turn into a failed eruption as there was a 5-hr pause in propagation before magma finally reached the surface. {U}nderstanding such unusual eruptions is a challenge for observatories as it may lead to repeated false alerts.},
keywords = {magma propagation ; inversion ; {GNSS} ; {I}n{SAR} ; magmatic intrusions ; numerical simulations ; {REUNION} ; {PITON} {DE} {LA} {FOURNAISE} {VOLCAN}},
journal = {{J}ournal of {G}eophysical {R}esearch : {S}olid {E}arth},
volume = {124},
numero = {2},
pages = {1361--1387},
ISSN = {2169-9313},
year = {2019},
DOI = {10.1029/2018jb016856},
URL = {http://www.documentation.ird.fr/hor/fdi:010075529},
}